This is the advice a professional gardening friend gave me when I had to make an emergency Spring transplant:

Soak the peonies; dig big root ball - packing the dirt toward the plant center with shovel as you dig. Put into large pot or burlap. Put compost into the new hole (prep the new area as early as possible with compost). Replant as soon as possible, being careful not plant deeply. Water well. She also recommended shading the plants during midday for awhile after the transplant.

I've done this and gotten blooms that very June...but you may have to wait a year for the plant to recover from the intrusion!

Good luck.
Judye

I transplanted 16 peony plants last fall(2006). We had a late winter, will I have blooms this spring? They are all starting to sprout through the ground now.
thx....